[Rockhounds] fossils

[Axel Emmermann]

It got through alright....

Fresh from the presses.

Thanks Earl

Axel Emmermann
European Regional Vice President of the
Fluorescent Mineral Society
<http://www.uvminerals.org/>
=========================
Mineralogische Kring Antwerpen/Antwerp Mineralogical Society
<http://www.minerant.org/index.html>
Werkgroepleider/Workgroup leader: Fluorescerende mineralen/Fluorescent
minerals
Technische Realisaties/Engineering
My website:<http://users.pandora.be/axel.emmerman/home/>


> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Earl R. Verbeek
> Verzonden: dinsdag 28 april 2009 18:46
> Aan: 'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'
> Onderwerp: RE: [Rockhounds] fossils
> 
> 
> Axel,
> ? I noticed your belimnites are chalcedony. Ours on this side of the
> Atlantic are the same color, but aragonite. You would have thought
> your chalcedony ones would be green, since many chaledony items
> fluoresce green here.
> dave
> 
> Hi Dave and Axel,
> 
> "Our" chalcedonies often fluoresce green due to trace amounts of uranyl
ion.
> This is particularly common in the desert Southwest, where volcanic rocks
> abound.  Uranium is strongly partitioned in silicic magmas and hence is
> concentrated in dacites and rhyolites, from which it is readily leached
into
> the groundwater system and incorporated into chalcedony vein fillings and
> "chalcedony roses" in large vesicles.  You'll see the same response, for
the
> same reasons, in much petrified wood.  In wood, however, there are also
> remnant organic molecules that often cause pale yellow to orange
> fluorescence, and in places you'll find this combined with the uranyl
green.
> I've seen many samples of chalcedony that fluoresce yellow, similar to
> Axel's belemnites.
> 
>              Cheers-    Earl
> 
> PS:  This note has been stuck in the queue for some time now, and I've no
> idea when it will be sent.  Had that same problem yesterday, too.
Apologies
> if this is "old news" by the time it's posted....
> 
> 
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